资 源 简 介
The LM1815 is an adapTIve sense amplifier and default gat-ing circuit for motor control applicaTIons. The sense amplifi-er provides a one-shot pulse output whose leading edgecoincides with the negaTIve-going zero crossing of a groundreferenced input signal such as from a variable reluctancemagneTIc pick-up coil.In normal operation, this timing reference signal is process-ed (delayed) externally and returned to the LM1815. A logicinput is then able to select either the timing reference or theprocessed signal for transmission to the output driver stage.The adaptive sense amplifier operates with a positive-goingthreshold which is derived by peak detecting the incomingsignal and dividing this down. Thus the input hysteresis var-ies with input signal amplitude. This enables the circuit tosense in situations where the high speed noise is greaterthan the low speed signal amplitude. Minimum input signalis 100 mVp-p.